Mirror drive device and method for producing same

Abstract

A mirror drive device includes a support part, a movable part, a permanent magnet forming a magnetic field in the periphery of the movable part, and a circuit board disposed between the support part and the permanent magnet in a facing direction of a pair of principal surfaces of the movable part so as to cause the movable part to be positioned at an inside of the circuit board when viewed in the facing direction. The movable part includes a mirror disposition portion, a mirror disposed and a drive coil so as to face the permanent magnet. The support part includes a base portion connected to a connection member and a reinforcing portion extending from the base portion toward a side away from the permanent magnet and the circuit board. The drive coil is connected to electrodes by lead-out conductors.

The invention claimed is: 
     
       1. A mirror drive device comprising:
 a support part having a frame-like shape; 
 a movable part positioned at an inside of the support part, having a first principal surface and a second principal surface located on opposite sides, and supported by the support part so as to be oscillated via a first connection member; 
 a magnetic body positioned to face the support part and the second principal surface in a direction in which the first principal surface and the second principal surface are arranged and forming a magnetic field in the periphery of the movable part; and 
 a circuit board having a frame-like shape and disposed between the support part and the magnetic body in the direction so as to cause the movable part to be disposed at an inside of the circuit board when viewed in the direction, 
 wherein the movable part includes:
 a base member including the first principal surface and the second principal surface, 
 a mirror disposed at the first principal surface side, and 
 at least one drive coil disposed at the second principal surface side so as to face the magnetic body, 
 
 wherein the support part includes:
 a base portion having a frame-like shape and connected to the first connection member, 
 a reinforcing portion having a frame-like shape and extending from the base portion toward a side away from the magnetic body and the circuit board in the direction, and 
 an electrode disposed at a position of the base portion, the position being on a surface side facing the magnetic body and overlapping with the reinforcing portion when viewed in the direction, 
 
 wherein the drive coil is connected to the electrode by a lead-out conductor extending from the movable part to the support part via the first connection member, 
 wherein the electrode is electrically connected to the circuit board, 
 wherein the movable part includes:
 a mirror disposition portion including a portion where the mirror is disposed in the base member, and 
 an outside portion including a frame-like portion surrounding an outer periphery of the mirror disposition portion in the base member, 
 
 wherein the at least one drive coil includes the two drive coils, 
 wherein the outside portion is supported by the support part so as to be oscillated via the first connection member, 
 wherein the mirror disposition portion is supported by the outside portion so as to be oscillated via a second connection member extending in a direction intersecting the first connection member, 
 wherein each of the two drive coils is wound in a spiral shape when viewed in a direction perpendicular to the second principal surface, 
 wherein a first drive coil of the two drive coils is disposed at the second principal surface side in the mirror disposition portion, 
 wherein a second drive coil of the two drive coils is disposed at the second principal surface side in the outside portion, 
 wherein in a surface of the magnetic body, the surface facing the second principal surface, a set of magnetic poles constituted by an S pole and an N pole arranged to be adjacent to each other in a direction along the surface is exhibited, and 
 wherein the second drive coil has a portion positioned in a first region in which a magnetic flux density in the magnetic field formed in the periphery of the movable part by the set of magnetic poles shows the substantially maximum value. 
 
     
     
       2. The mirror drive device according to  claim 1 ,
 wherein the circuit board is disposed at a surface of the magnetic body, the surface facing the second principal surface. 
 
     
     
       3. The mirror drive device according to  claim 1 ,
 wherein, in the direction, a sum of thicknesses of the base portion and the reinforcing portion is greater than a thickness of the movable part. 
 
     
     
       4. The mirror drive device according to  claim 1 , further comprising:
 a bump electrode disposed between the circuit board and the support part and connecting the circuit board to the electrode. 
 
     
     
       5. The mirror drive device according to  claim 1 ,
 wherein the base member includes a groove portion disposed at the second principal surface side and extending in the spiral shape when viewed in the direction perpendicular to the second principal surface, and 
 wherein the drive coil is formed of a first metallic material disposed in the groove portion and is wound in the spiral shape when viewed in the direction perpendicular to the second principal surface. 
 
     
     
       6. The mirror drive device according to  claim 5 , wherein the movable part further includes:
 a coating layer covering an opening of the groove portion and formed of a second metallic material that suppresses diffusion of the first metallic material, and 
 
       an insulating layer disposed on the second principal surface and the coating layer. 
     
     
       7. The mirror drive device according to  claim 6 ,
 wherein the first metallic material is Cu or Au, and 
 wherein the second metallic material is Al or an alloy containing Al. 
 
     
     
       8. The mirror drive device according to  claim 5 ,
 wherein the movable part further includes an insulating layer covering the opening of the groove portion. 
 
     
     
       9. The mirror drive device according to  claim 8 ,
 wherein a material forming the insulating layer is SiN, and 
 wherein a thickness of the insulating layer is 50 nm or greater. 
 
     
     
       10. The mirror drive device according to  claim 1 ,
 wherein the magnetic body has a first magnetic portion, a second magnetic portion and a third magnetic portion which are sequentially arranged to form a Halbach array along a predetermined direction, and 
 wherein the second drive coil has a portion positioned in the first region. 
 
     
     
       11. The mirror drive device according to  claim 1 ,
 wherein the magnetic body includes:
 a first magnetic portion and a second magnetic portion which are adjacent to each other along a first direction perpendicular to the facing direction, 
 a third magnetic portion and a fourth magnetic portion which are adjacent to each other along the first direction, and 
 a fifth magnetic portion and a sixth magnetic portion which are arranged along a second direction perpendicular to both the facing direction and the first direction, 
 
 wherein the fifth and sixth magnetic portions are positioned between the second and third magnetic portions and are adjacent to the second and third magnetic portions in the first direction, 
 wherein a magnetization direction of each of the first, third and fifth magnetic portions is directed from the first principal surface side toward the second principal surface side, 
 wherein a magnetization direction of each of the second, fourth and sixth magnetic portions is directed from the second principal surface side toward the first principal surface side, and 
 wherein the second drive coil has a portion positioned in the first region. 
 
     
     
       12. The mirror drive device according to  claim 11 ,
 wherein the first drive coil has a portion positioned in a second region other than the first region. 
 
     
     
       13. A method of manufacturing a mirror drive device comprising:
 preparing a circuit board having a frame-like shape; 
 preparing a mirror structure which includes a support part having a frame-like shape, and a movable part positioned at an inside of the support part, having a first principal surface and a second principal surface located on opposite sides, and supported by the support part so as to be oscillated via a connection member, in which the movable part includes a base member including the first principal surface and the second principal surface, a mirror disposed at the first principal surface side, and a drive coil disposed at the second principal surface side, the support part includes a base portion having a frame-like shape and connected to the connection member, a reinforcing portion having a frame-like shape and extending from the base portion in a direction from the second principal surface toward the first principal surface, and an electrode disposed at a position of the base portion, the position being on a surface side opposite to the reinforcing portion and overlapping with the reinforcing portion when viewed in the direction, and the drive coil is connected to the electrode by a lead-out conductor extending from the movable part to the support part via the connection member; 
 preparing a magnetic body forming a magnetic field in the periphery of the movable part, the magnetic body having a part which faces the movable part and is exposed through the inside of the circuit board when viewed in the direction; 
 assembling the mirror structure, a magnetic body, and a circuit board such that the magnetic body faces the support part and the second principal surface in the direction, and that the reinforcing portion, the base portion, the electrode, the circuit board, and the magnetic body overlap in this order in the direction, thereby electrically and physically connecting the circuit board to the electrode. 
 
     
     
       14. The method according to  claim 13 , further comprising:
 disposing the circuit board on a portion of a surface of the magnetic body after the preparation of the mirror structure and before the electrical connection of the circuit board to the drive coil. 
 
     
     
       15. The method according to  claim 13 , further comprising:
 disposing a bump electrode on the electrode after the preparation of the mirror structure and before the electrical connection of the circuit board to the drive coil, 
 wherein, when the circuit board and the drive coil are electrically connected to each other, the bump electrode is connected to the circuit board, thereby assembling the mirror structure and the bump electrode with the magnetic body and the circuit board. 
 
     
     
       16. A mirror drive device comprising:
 a support part having a frame-like shape; 
 a movable part positioned at an inside of the support part, having a first principal surface and a second principal surface located on opposite sides, and supported by the support part so as to be oscillated via a first connection member; 
 a magnetic body positioned to face the support part and the second principal surface in a direction in which the first principal surface and the second principal surface are arranged and forming a magnetic field in the periphery of the movable part; and 
 a circuit board having a frame-like shape and disposed between the support part and the magnetic body in the direction so as to cause the movable part to be disposed at an inside of the circuit board when viewed in the direction, 
 wherein the magnetic body includes an exposed part which faces the movable part and is exposed through the inside of the circuit board when viewed in the direction, 
 wherein the movable part includes:
 a base member including the first principal surface and the second principal surface, 
 a mirror disposed at the first principal surface side, and 
 at least one drive coil disposed at the second principal surface side so as to face the exposed part, 
 
 wherein the support part includes:
 a base portion having a frame-like shape and connected to the first connection member, 
 a reinforcing portion having a frame-like shape and extending from the base portion toward a side away from the magnetic body and the circuit board in the direction, and 
 an electrode disposed at a position of the base portion, the position being on a surface side facing the magnetic body and overlapping the reinforcing portion when viewed in the direction, 
 
 wherein the reinforcing portion, the base portion, the electrode, the circuit board, and the magnetic body overlap in this order in the direction, 
 wherein the drive coil is connected to the electrode by a lead-out conductor extending from the movable part to the support part via the first connection member, and 
 wherein the electrode is electrically and physically connected to the circuit board. 
 
     
     
       17. The mirror drive device according to  claim 16 , wherein the circuit board is disposed at a surface of the magnetic body, the surface facing the second principal surface. 
     
     
       18. The mirror drive device according to  claim 16 , wherein, in the direction, a sum of thicknesses of the base portion and the reinforcing portion is greater than a thickness of the movable part. 
     
     
       19. The mirror drive device according to  claim 16 , further comprising a bump electrode disposed between the circuit board and the support part and connecting the circuit board to the electrode. 
     
     
       20. The mirror drive device according to  claim 16 ,
 wherein the base member includes a groove portion disposed at the second principal surface side and extending in a spiral shape when viewed in a direction perpendicular to the second principal surface, and 
 wherein the drive coil is formed of a first metallic material disposed in the groove portion and is wound in a spiral shape when viewed in the direction perpendicular to the second principal surface. 
 
     
     
       21. The mirror drive device according to  claim 20 ,
 wherein the movable part further includes:
 a coating layer covering an opening of the groove portion and formed of a second metallic material that suppresses diffusion of the first metallic material, and 
 an insulating layer disposed on the second principal surface and the coating layer. 
 
 
     
     
       22. The mirror drive device according to  claim 21 ,
 wherein the first metallic material is Cu or Au, and 
 wherein the second metallic material is Al or an alloy containing Al. 
 
     
     
       23. The mirror drive device according to  claim 20 , wherein the movable part further includes an insulating layer covering the opening of the groove portion. 
     
     
       24. The mirror drive device according to  claim 23 ,
 wherein a material forming the insulating layer is SiN, and 
 wherein a thickness of the insulating layer is 50 nm or greater. 
 
     
     
       25. The mirror drive device according to  claim 16 ,
 wherein the movable part includes:
 a mirror disposition portion including a portion where the mirror is disposed in the base member, and 
 an outside portion including a frame-like portion surrounding an outer periphery of the mirror disposition portion in the base member, 
 
 wherein the at least one drive coil includes the two drive coils, 
 wherein the outside portion is supported by the support part so as to be oscillated via the first connection member, 
 wherein the mirror disposition portion is supported by the outside portion so as to be oscillated via a second connection member extending in a direction intersecting the first connection member, 
 wherein each of the two drive coils is wound in a spiral shape when viewed in a direction perpendicular to the second principal surface, 
 wherein a first drive coil of the two drive coils is disposed at the second principal surface side in the mirror disposition portion, 
 wherein a second drive coil of the two drive coils is disposed at the second principal surface side in the outside portion, 
 wherein in a surface of the magnetic body, the surface facing the second principal surface, a set of magnetic poles constituted by an S pole and an N pole arranged to be adjacent to each other in a direction along the surface is exhibited, and 
 wherein the second drive coil has a portion positioned in a first region in which a magnetic flux density in the magnetic field formed in the periphery of the movable part by the set of magnetic poles shows the substantially maximum value. 
 
     
     
       26. The mirror drive device according to  claim 16 ,
 wherein the magnetic body has a first magnetic portion, a second magnetic portion and a third magnetic portion which are sequentially arranged to form a Halbach array along a predetermined direction, and 
 wherein the second drive coil has a portion positioned in the first region. 
 
     
     
       27. The mirror drive device according to  claim 16 ,
 wherein the magnetic body includes:
 a first magnetic portion and a second magnetic portion which are adjacent to each other along a first direction perpendicular to the direction, 
 a third magnetic portion and a fourth magnetic portion which are adjacent to each other along the first direction, and 
 a fifth magnetic portion and a sixth magnetic portion which are arranged along a second direction perpendicular to both the direction and the first direction, 
 
 wherein the fifth and sixth magnetic portions are positioned between the second and third magnetic portions and are adjacent to the second and third magnetic portions in the first direction, 
 wherein a magnetization direction of each of the first, third and fifth magnetic portions is directed from the first principal surface side toward the second principal surface side, 
 wherein a magnetization direction of each of the second, fourth and sixth magnetic portions is directed from the second principal surface side toward the first principal surface side, and 
 wherein the second drive coil has a portion positioned in the first region. 
 
     
     
       28. The mirror drive device according to  claim 27 , wherein the first drive coil has a portion positioned in a second region other than the first region.